This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The Division of Immunology provides a broad array of immunological and virological reagents to investigators involved in AIDS, gene therapy and hematopoeisis research. Examples of reagents provided by the Division of Immunology include samples of rhesus macaque bone marrow, lymphocytes and thymocytes, cryopreserved rhesus thymic stroma, monoclonal antibodies specific for macaque T cells, peptides used for immunological assays of cell-mediated immune responses, the S594 cell line (a producer cell line for herpesvirus papio, which is routinely used for the transformation of macaque B cell lines) and retroviral vectors and packaging lines. Provision of rhesus thymic stroma to outside investigators represents a particularly unique resource;this reagent supports the in vitro T cell differentiation of both monkey and human CD34-positive progenitor cells, a process that has traditionally required in vivo studies.